Depending upon the sport, a variety of traction members, cleats and lugs are used in different orientations in order to improve the traction afforded by the athletic shoe. For example, metal or plastic cleats are often used for baseball and football footwear and metal spikes are generally preferred for running and soccer footwear. The cleats or the like can be integrally formed with the sole of the shoe or, alternatively, the cleats can be replaceable. When using replaceable cleats, the service life of the shoe is extended because a damaged or worn cleat can merely be replaced rather than having to discard the entire shoe. Replaceable cleats generally have a threaded screw attachment element and a similar threaded receptacle is provided in the sole of the shoe. However, the placement of a threaded receptacle in the sole plate increases the thickness and the weight of the athletic shoe, as well as the manufacturing costs. Replaceable cleats also have a tendency to become dislodged during use and often require special tools or a screwdriver for removal, thus detracting from their initial appeal.
For example, U.S. Pat. No. 4,712,318 to Greiner et al. discloses a gripping element having a metal shank portion with a male screw thread thereon for fixing the gripping element to the sole of a sports shoe. Thus, the thickness of the sole must be increased to accommodate the screw thread connection.
U.S. Pat. No. 4,299,038 to Epple discloses an outer sole equipped with replaceable synthetic insert elements adapted to be threadedly secured in overlapping relationship to raised projections on the sole exterior. The insert elements are adapted to receive and retain conventional spikes or the insert elements can include integrally formed gripping projections. The threaded sole openings which receive the insert elements again require an increased sole thickness in order to assure a secure connection therebetween. In addition, a special tool or the metal spike itself must be used to attach the insert element to the threaded sole opening.
U.S. Pat. No. 3,911,600 to Dassler further provides an exchangeable gripper element having a steep thread in the form of one or more helical ribs or grooves, and a locking element in the form of a projection or recess disposed on the threaded extension. Thus, the gripping element is secured against undesired loosening in use. However, the increased sole thickness is still mandated by the prior art screw thread connection.